Upper thermal tolerance of closely related Danio species. Issue 4 (April 2014)

• Record Type: Journal Article
• Authors: Sidhu, R.; Anttila, K.; Farrell, A. P.
• Is Part Of: Journal of fish biology. Volume 84:Issue 4(2014)
• Page Start: 982
• Page End: 995
• Publication Date: 2014-04
• Subjects: Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.12339
• Languages: English
• ISSNs: 0022-1112

Abstract

<abstract abstract-type="main" id="jfb12339-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="jfb12339-para-0001">The main finding of this study was that measuring maximum heart rate during incremental warming was an effective tool to estimate upper thermal limits in three small cyprinid <italic>Danio</italic> species, which differed significantly. Arrhenius breakpoint temperature for maximum heart rate, purportedly an index of optimum temperature, was 21·2 ± 0·4, 20·1 ± 0·4 and 18·9 ± 0·8° C (mean ± <sc>s.e</sc>.) for zebrafish <italic>Danio rerio</italic>, pearl danio <italic>Danio albolineatus</italic> and glowlight danio <italic>Danio choprae</italic>, respectively. The temperature where cardiac arrhythmias were first induced during warming (<italic>T</italic><sub>arr</sub>) was 36·6 ± 0·7, 36·9 ± 0·8 and 33·2 ± 0·8° C (mean ± <sc>s.e</sc>.) and critical thermal maximum (<italic>T</italic><sub>Cm</sub>) was 39·9 ± 0·1, 38·9 ± 0·1 and 37·2 ± 0·1° C (mean ± <sc>s.e</sc>.) for <italic>D. rerio</italic>, <italic>D. albolineatus</italic> and <italic>D. choprae</italic>, respectively. The finding that <italic>T</italic><sub>arr</sub> was consistently 3–4° C lower than <italic>T</italic><sub>Cm</sub> suggests that collapse of the cardiac life support system may be a critical trigger for upper temperature tolerance. The upper thermal limits established here, which correlate well with a broad natural environmental temperature range for <italic>D. rerio</italic> and a narrow one for <italic>D. choprae</italic>, suggest that upper thermal tolerance may be a genetic trait even among closely related species acclimated to common temperatures.</p> </abstract>